Fuel-injector for internal-combustion engines.



H. F. SHEPHERD. FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED AUG-12; 1914.

Patentd Dec.14,1915.

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HAROLD F. SHEPHERD, OF GROVE CITY, PENNSYLVANIA, ASSIGNOR TO BESSEMER GAS ENGINE COMPANY, OF GROVE CITY, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

Specification of Letters Patent.

Patented Dec. 14, 1915.

Application filed August 12, 1914.. Serial No. 856,391.

To all whom it may concern Be it known that I, HAROLD F. SHEP- nnno, a citizen of the United States, residing at Grove City, in the county of Mercer and State of Pennsylvania, have invented new and useful Improvements in F uel-Injectors for Internal-Combustion ,Engines, of which the following is a specification.

This invention relates to fuel injectors for internal combustion engines and consists in certain improvements in the construction thereof as will be hereinafter fully described and pointed out in the claims.

In the preferable form, the invention is adapted to internal combustion engines using heavy hydrocarbons and utilizing a heated surface, commonly termed a hotbulb, for vaporizing the fuel.

So adapted the invention involves the injection of fuel during a comparatively small part of the cycle of the engine.

The present invention also involves in its preferred form a mechanism for actuating the fuel injector under varying conditions of load to vary the fuel injected and this preferably during a fixed period in the cycle of the engine.

The broader features, as well as the details of construction will appear from the specification and claims.

The invention is illustrated in the accompanying drawings as follows Figure 1 shows a fuel injector, partly in section. Fig. 2 a side elevation of the cam for operating the releasing valve. Fig. 3 an enlarged view of the valve of the fuel injector pump.

The fuel injector comprises a pump cham-- her 1. The inlet 2 leads to this chamber and the chamber is provided with the discharge 3. An inlet valve 4 controls the inflow of fuel and the discharge valve 5 prevents a return flow of fuel after its discharge. ;The inlet valve is held to its seat by a spring 6 and the discharge va-lve by a spring 7. A'plunger bore 8 communicates with the chamber 1 and is arranged in a projection 8 from the body of the chamber 1. The plunger 9 operates in the bore 8. It is provided with a cross head 10 at its outer end which slides in the guides 11 carried by the frame 12, the frame 12 being mounted on the extension 8.

It will be readily observed that as the pump plunger 9 operates, fuel will be drawn in through the inlet 2 and when the inlet valve is closed will be discharged through the discharge opening 3, a return flow of fuel being prevented by the valve 5. It is desirable to vary this charge and it is also deslrable to have the charge delivered durmg a fixed period in the cycle of the engine. Icontrol the period through which the liq uid is discharged by actuating the inlet valve, or in relation to this function, the releasing valve during a period of the dis charge stroke of the plunger so that the discharge through the valve 5 takes place only during a part of the discharge stroke of the plunger.

In order to vary the stroke of the plunger, I provide the following mechanism: An eccentric rod 13 extends from the cross head 10 to the strap 14. The strap 14 operates on the eccentric 15. The eccentric 15 is carried by a swinging mounting 16, the swinging mounting being pivotally supported by a pin 17. The pin 17 extends from the fly wheel 18. The fly wheel 18 is carried by the crank shaft 19 of the engine (not shown). An arm 20 extends from the swinging mounting 16 and is pivotally connected by means of a pin 21 with the governor weight 22. The governor weight 22 is preferably in the form of a ring as shown and mounted on a pin 23 extending from the fly wheel 18. A spring 24 is provided forming the centripetalelement of the governor. The ordinary stops 25 are also provided as well as the common dash pot 26. The governor operates in the manner of centrifugal governors, that is to say, as the speed increases the weight moves away from the center and this operating through the arm 20 and mounting 16 swings the eccentric toward the center, or reduces the throw of the eccentric and a variation in the throw of the eccentric varies the movement of the plunger.

In order to control the period through which there is a discharge of fuel so that it may properly synchronize with the engine to which the injector is attached, I provide the following mechanism :The inlet valve 4: operates on the seat 27 and this seat is on the end of a bushing 28 arranged within an extension 29 on the pump chamber. The bushing 28 is spaced from the walls 29 forming an annular space 30 from which the inlet openings 31 lead and to which the inlet 2 leads, thus distributing the inlet passage. The inlet valve 4 has a stem 32 terminating in a webbed or winged portion 33. An auxiliary valve 34 is arranged in the inlet valve 4 and the spring 6 operates directly on the valve 34. The valve 34 operates on the seat 35 on the valve 4. It is provided with a stem 36 terminating with a head 37, the head 37 being slightly above the wings 33 so as to give the auxiliary valve 34 a limited movement relatively to the valve 4. The auxiliary valve 34 is actuated by a plunger 38. The plunger in its operation picking up first the auxiliary valve 34 by operating on the head 37 and upon a continuation of its movement picking up the valve 4 through the stems 32 and 33. The purpose of the auxiliary valve is to reduce the force necessary to open the inlet valve. By first opening the auxiliary valve, the pressures are allowed to balance on the inlet valve. Then with a further movement of the plunger, the inlet valve can be easily opened.

' The plunger 38 operates in a bushing 39 arranged in the extension 29. It terminates in a head 40. A spring 41 is arranged under the head 40 and tends to lift the plunger. A rock arm 42 is mounted on a pin 43, the pin 43 being carried by a frame 44 extending from the body of the pump chamber. An adjusting screw 45 is provided and forms the point of contact between the rock'arm and the plunger 38. A push rod 46 is connected with the rock arm 42 by means of a pin-47. The push rod is operated upon by a cam 48, the cam being circular ordinarily throughout about 340 and having a depressed surface 49 extending over about 20. The ordinary cam roller 50 is provided on the end of the push rod 46 and the push rod is supported by a rock arm 51 carried by a base 52. It will be understood that the cam 48 is mounted on the crank shaft 19 and moves synchronously with the plunger actuating mechanism.

The depression on the cam 48 is arranged With relation to the throw of the eccentric so that the inlet valve or releasing valve considered with the function now under consideration is maintained in an open position except during the period in the cycle of the parts during which the depression 49 is in engagement with the roller 50, that is to say,

about 20 of the entire revolution. During this movement of the 20 of the crank shaft, the inlet valve 4 is closed and during this period the pump plunger is about-the middle of its discharge strokeand fuel is discharged past the discharge valve during this period. It will be observed that the discharge in this pump takes place with the eccentric on the quarter and'vvith the plunger practically in the middle of its movement and that the inlet valve or releasing device for the liquid in the pump chamber is opened at the be ginning and at the end of the discharge stroke of the plunger. lVith many engines, the discharge must be confined to this relatively short period relatively to the whole cycleand in order to accomplish this where the discharge is at the end of the stroke of the pump plunger, the pump plunger must be made of comparatively large area because the travel at the ends of the stroke is relatively slow. \Vith this construction by reason of the fact that the discharge is at the fastest travel of the plunger, the area of the plunger can be comparatively small and in consequence the thrust on the connecting parts is reduced. When it is considered that in most of these injectors very high pressures are used this is of great advantage.

In order that the thrust necessary to operate the plunger may disturb the governor as little as possible, I prefer to so arrange the swinging mounting 16 with relation to the eccentric that the axis of the swinging mounting will pass the line of strain as indicated by the line XX in Fig. 1 between the eccentric and the plunger and I prefer that the path of the axis of the swinging mounting shall extend approximately equal at each side of the line of strain during this discharge movement. In this way, the direction of forces tending to move the eccentric toward and from the center is reversed so that any disturbance from the thrust incident to the discharge stroke is approximately equalized as well as minimized.

What I claim as new is 1. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in said chamber; means for varying the stroke of the plunger; and devices for releasing the liquid from the chamber during relatively to the movement of the plunger in its discharge stroke, the period of closing said devices being fixed with relation to the cycle of the injector.-

3. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in a said chamber; means for varying the stroke of the plunger; and devices for releasing the liquid from the chamber during a portion of the discharge stroke ofthe plunger and for closing said devices during an intermediate period with relation to the movement of the plunger in its discharge stroke, the period of closing said devices being fixed with relation to the cycle of the injector.

4. In a fuel injector for internal combus tion engines, the combination of a pump chamber; a plunger operating on the liquid insaid chamber; a shaft governor actuating said plunger; and devices for releasing the liquid from the chamber during a portion of the discharge stroke ofthe plunger and for closing said devices to force a discharge of fuel during a fixed period in the cycle of the injector.

5. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid. in said chamber; a shaft governor actuating the plunger; and devicesfor releasing the liquid from the chamber during a portion of the discharge stroke of the plunger and for closing said devices to force a discharge during an intermediate period relatively to the movement of the plunger in its discharge stroke, the-period of closing said devices being fixed with relation to the cycle of the injector.

6. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in said chamber; a releasing valve for said chamber; means for opening said valve during the discharge stroke of the plunger; and an auxiliary valve operating in connection with the releasing valve and actuated initially to relieve the pressure on said releasing valve.

7. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in said chamber; a shaft governor actuating the plunger, said governor comprising an eccentric; a swinging mounting for the eccentric; centrifugal and centripetal elements operating on the eccentric; and a connection between the plunger and the eccentric, the axis of the swinging mounting passing the line of strain between the connection and the eccentric during the discharge from the Pu p- 8. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in said chamber; a shaft governor actuating the plunger, said governor comprising an eccentric; a swinging mounting for the eccentric; centrifugal'and centripetal elements operating on the eccentric; a connection between the plunger and the eccentric, the axis of the swinging mounting passing the line of strain between the connection and the eccentric during the discharge from the pump; and devices for releasing the liquid of the swinging mounting passing the line of strain between the connection and the eccentric during the discharge from the pump; and devices for releasing the liquid from the chamber during an intermediate period of the discharge stroke of the plunger and for closing said devices to force a discharge of fuel during a fixed period in the cycle of the injector.

10. In a fuel injector for internal combustion engines, the combination of a pump chamber; a plunger operating on the liquid in said chamber; a shaft governor actuating the plunger, said governor comprising an eccentric; a swinging mounting for the eccentric; centrifugal and centripetal elements operating on the eccentric; and a connection between the plunger and the eccentric, the axis of the swinging mounting passing the line'of strain between the connection and the eccentric during the discharge from the pump, the path of the axis each side of the line of strain during the discharge movement being approximately equal.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

HAROLD F. SHEPHERD. Witnesses:

E. J. FITHIAN, WM. J. SLOAN.

Copies of this patent may be obtained'for flve cents each, by addressing the Commissioner of Patents.

' Washington. D. G. 

